Demolition of the rest of Terminal 2 will begin in January 2010
Demolition of the oldest building at west London's Heathrow Airport has begun as part of a £1bn refurbishment.
The Queen's Building at Terminal 2, which opened in 1955, will be knocked down by January 2010 when demolition of the rest of the terminal will begin.
Terminal 2 serves eight million passengers per year but it will serve 20 million when refurbishment is complete in 2013, operator BAA said.
Critics say the expanded capacity could mean more disruption to residents.
Demolition of the Queen's Building began at 1400 BST. Flights bound for Terminal 2 are being diverted to other Heathrow terminals.
The new Terminal 2 will be home to Star Alliance airlines as part of its £4.8bn investment in the airport.
By 2019 the new terminal will extend into the current Terminal 1 site to give a joint capacity of 30 million passengers.
BAA said expansion was "crucial" for Heathrow to remain competitive.
But anti-airport expansion group Hacan Clear Skies said it was concerned that greater passenger capacity would result in more flights and greater disturbance to residents in west London and Berkshire.